Synthetic absorbable polymers have been used to produce various surgical products such as sutures, implants, prostheses, and the like, for several years. Illustrative U.S. patents that disclose such polymers are U.S. Pat. Nos. 3,297,033, 3,044,942, 3,371,069, 3,531,561, 3,636,956, RE 30,170, and 4,052,988.
Implantable surgical devices must be sterile prior to implanting in the body. Sterilization of devices is usually accomplished by the use of heat, ethylene oxide, or gamma radiation using a .sup.60 Co source. In many cases, the use of gamma radiation is the most convenient and most certain way to effect sterilization. However, all of the synthetic absorbable polymers now in commercial use are significantly degraded by gamma radiation. Therefore, unless for some reason degradation of the polymer is desired (for instance, to greatly accelerate the absorption rate), the use of gamma radiation is precluded for the purpose of sterilizing the presently commercial synthetic absorbable polymners.
This invention provides a new class of polymers that are absorbable and which can be sterilized by gamma radiation while still retaining a desirable level of physical and biological properties.